exercising in the heat - lesson 3

Question 1

what are the 5 strategies to aid performance in the heat?

Answer 1

1. hyperhydration pre-exercise
2. hydration
3. cooling strategies
4. clothing
5. heat acclimatisation

Question 2

what is hyperhydration pre-exercise?

Answer 2

involves consuming excess fluid in the hours prior to performance

• 600ml 3 – 4 hours before
• 400ml just prior
• avoid caffeine = diuretic = fluid loss

Question 3

what is hydration?

Answer 3

• during and after exercise
• maintains fluid levels and compensate for fluid losses
• approx 200ml of water every 15min during activit

Question 4

define hyponatremia

Answer 4

An abnormally low concentration of sodium (salt / electrolytes) in the blood.

Question 5

why are sports drinks effective?

Answer 5

• Taste good meaning athlete wants to drink more
• Provide athlete with rapid supply of energy (high GI) and assist in glycogen sparing
• Replace lost electrolytes (particularly effective in ultra endurance activities where massive amounts of sweat loss and electrolyte loss occurs)
• Contain carbohydrates, sodium and potassium
• Rehydrate the performer

Question 6

what are cooling strategies?

Answer 6

• ice vest / cold water immersion: pre cooling body pre performance = lower core temp = better performance
• drinking slushies
• going in shade

Question 7

describe how clothing is a strategy used in heat

Answer 7

• Wear thin, light-colored, breathable clothing = effective evaporation and convection in order to cool the body down

Question 8

describe heat acclimatization

Answer 8

when heat tolerance is improved due to repeated exposure to hot environments

Question 9

how do athletes heat acclimatize?

Answer 9

• 5-10 days living and training in heat
• the first session = 15-20 minutes and consist of light to moderate activity.
• increase to 45-60min daily for approx 8-9 days with an increase in exercise intensity & duration.
• completed 4-6weeks prior
• never restrict fluids
• does not go beyond 14 days

Question 10

what are the 5 physiological outcomes of heat acclimatization?

Answer 10

1. increase sweat rate
2. faster onset of sweating
3. increase in blood plasma
4. sweat becomes more filute
5. effective distribution of sweat

Question 11

describe the 1st physiological outcomes of heat acclimatization?

Answer 11

increased sweat rate

• sweat glands increase in size
• Sweat rate can almost double after 10 days of acclimatisation

Question 12

describe the 2nd physiological outcome of heat acclimatization?

Answer 12

faster onset of sweating

• you start sweating at a lower core temperature = lower heart rate = lower skin temperature at any given intensity.
• A lower core temperature = more blood to be sent to the working muscles

Question 13

describe the 3rd physiological outcome of heat acclimatization?

Answer 13

An increase in blood plasma volume

• leads to an increase in cardiac output which minimises the implications of competition for blood flow
• Delays dehydration and allows for better evaporative cooling and oxygen delivery to the muscles.

Question 14

describe the 4th physiological outcome of heat acclimatization?

Answer 14

Sweat becomes more dilute

- less salt loss which preserves essential electrolytes

Question 15

describe the 5th physiological outcome of heat acclimatization?

Answer 15

Effective distribution of sweat

- The body uses a greater surface area for evaporative cooling leading to better maintenance of core temperature.